Dicyanobenzene can be produced by known methods of ammoxidizing xylene (ortho-xylene, meta-xylene, para-xylene), and can be produced, for example, by the methods described in Patent Literatures 1 to 8.
Various methods have been disclosed for production of xylylenediamine by subjecting dicyanobenzene to liquid-phase hydrogenation in the presence of a catalyst. For example, Patent Literature 9 states that a batch-wise hydrogenation reaction on dicyanobenzene is carried out in an alcohol-based solvent in an autoclave using a small amount of a caustic alkali agent together with Raney nickel or Raney cobalt to obtain corresponding xylylenediamine. Patent Literature 10 states that a catalytic reduction on dicyanobenzene with hydrogen is carried out in a liquid phase via a nickel-copper-molybdenum-based catalyst, illustrating a fixed-bed continuous hydrogenation.
Patent Literature 11 describes a method for producing meta-xylylenediamine, including: a first distillation step of separating impurities having a boiling point higher than isophthalonitrile from isophthalonitrile obtained by an ammoxidation reaction on meta-xylene; a second distillation step of separating an organic solvent and hydrogenating the isophthalonitrile obtained from a column bottom, by adding a specific solvent and liquid ammonia thereto. Patent Literature 12 describes a method for producing xylylenediamine, including: bringing a xylene-ammoxidation reaction gas into contact with an organic solvent or molten dicyanobenzene; separating a component having a boiling point lower than dicyanobenzene from the resulting organic solvent solution or suspension or dicyanobenzene melt; subsequently removing a component having a boiling point higher than dicyanobenzene; and then hydrogenating the dicyanobenzene.
Patent Literature 13 states that when dicyanobenzene is hydrogenated, benzamide compounds or benzoic acid compounds, which are impurities having a boiling point higher than dicyanobenzene, are separated by distillation to keep the concentration of the benzamides or benzoic acid compounds in the hydrogenation reaction solution at a specific level or lower, thereby producing xylylenediamine in a high yield and prolonging the catalyst service life. Patent Literature 14 describes a method for producing xylylenediamine, including: separating by distillation a component having a boiling point lower than dicyanobenzene from an organic solvent solution obtained by bringing a xylene-ammoxidation reaction gas into contact with an organic solvent; then, dissolving molten dicyanobenzene in a solvent containing liquid ammonia; and subjecting precipitates containing dicyanobenzene polymers to solid-liquid separation and hydrogenation.
Patent Literature 15 describes a method for producing xylylenediamine, including: bringing a xylene-ammoxidation reaction gas into contact with an organic solvent; and carrying out a hydrogenation reaction on dicyanobenzene absorbed in the organic solvent, without separation, by adding liquid ammonia. Patent Literature 16 describes a method for producing xylylenediamine, including: bringing a xylene-ammoxidation reaction gas into contact with an organic solvent or molten dicyanobenzene; separating a component having a boiling point lower than dicyanobenzene from the obtained organic solvent solution or suspension or dicyanobenzene melt; and then carrying out hydrogenation of the dicyanobenzene without removing a component having a boiling point higher than dicyanobenzene.